Compression and expander rings are widely used in the assembly of pistons for internal combustion engines. Compression rings typically are made of cast iron or steel and precision ground so as to be nearly perfectly flat and thus resistant (stiff) to bending out of a flat profile. Compression rings can be from 3 mm to 1 mm in thickness and have square or radiused inner diameters.
Expander rings, on the other hand, typically are made of stainless steel and include vertical and/or horizontal corrugations. Expander rings are relatively flimsy and easily bendable out of a flat profile as compared to compression rings during the assembly operation into the respective piston grooves. Expander rings can be from 4 mm to 1 mm in thickness.
Internal combustion engine pistons typically have several rings positioned in respective circumferential grooves proximate the closed (domed) end of the piston. For example, a typical internal combustion engine piston will include an inner expander ring with so-called rail rings on opposite sides thereof in the same groove, an intermediate cast iron compression ring, and cast iron or steel outer compression ring proximate the closed (domed) end of the piston.
There is a need for piston ringing apparatus that can be used to assemble the compression and expander rings onto internal combustion engine pistons at one or more piston ringing stations under high volume production conditions where lengthy interruptions or downtime in the piston ringing operation due to the need to supply rings to the ringing station(s) is avoided.
There also is a need for piston ringing apparatus that can be used to assemble compression and expander rings onto internal combustion engine pistons at one or more piston ringing stations and that can be further automated in a manner that improves the assembly rate and reliability of ring/piston assembly.
It is an object of the invention to satisfy these needs.